[Resuelto] translate

Background of the issue:
I am trying to translate custom fields using WPML. I have five fields, and I have translated all of them, one of them which is the 'Οικογενειακό όνομα' (family name) and it doesnt translate. The issue can be seen on this page: enlace oculto

Symptoms:
The 'Οικογενειακό όνομα' field is not translated into English as expected.

Questions:
Why is the 'Οικογενειακό όνομα' field not translating?
How can I ensure all custom fields are translated correctly?